Add Gradle Plugin Portal publication to the buildscripts

Add option to disable signing (-PnoSign), to be used when publishing
pre-built artifacts

Add option to define specific version for publishing, to be used when
publishing test versions

(cherry picked from commit dcd55e9)

libraries/tools/kotlin-noarg/build.gradle

@@ -39,4 +39,17 @@ compileKotlin.dependsOn preprocessSources
 
 jar {
     from(targetSrc) { include("META-INF/**") }
+}
+
+pluginBundle {
+    plugins {
+        kotlinNoargPlugin {
+            id = 'org.jetbrains.kotlin.plugin.noarg'
+            description = displayName = 'Kotlin No Arg compiler plugin'
+        }
+        kotlinJpaPlugin {
+            id = 'org.jetbrains.kotlin.plugin.jpa'
+            description = displayName = 'Kotlin JPA compiler plugin'
+        }
+    }
 }